Surface-sizing of fibrous void-containing sheets with hydrous zirconium compounds



United States Patent'Q SURFACE-SIZING 0F FIBROUS VOID-CONTAIN- ING SHEETS WITH HYDROUS ZIRCONIUM COMPOUNDS Stewart M. Beeklnan, Berkeley Heights, N.J., and John F. Cipriano, Philadelphia, Pal, 'as signors' of one-half to Reheis Company, Inc'., a corporation of New Yu -hand one-half to Adelphi' Research & Manufacturing 'Coin P y; 'm h l A i No Drawing. Filed Sept. 1, 19 55, Ser. No. 532,125 2 Claims (c wa This invention relates to the surface-sizing of fibrous base material. The invention is particularlyuseful in making a photosensitive paper and 'will be first illustrated by description in connection with such use.

The art f making such photosensitive sheet including aluminum basic carbonate gel has been described in U.S1 latent Np. 2,7 QS, 6;85, issued to John F; Cipriano on April 5,1955. e v We have now discovered a surface-sizing position and process for paper and like sh eet material which serves to Id 1116,; on'the surface of the sheet material, photosensit r emis b Q other s a l p s later 12 pliedthereto. The result is'incr eased utility of the photose'nsitive composition,'which gives clearer prints, for example, in use of the product in "reproducing engineering Briefly stated, our invention comprises the herein descrihed process of and product resulting fr'drn applying, over a fibrous sheetfan aqueous dispersion of'an "adhesive and, suspended therein, azirconium compoundofspecial kind, the zirconium compound and adhesivebe'ing' used amount tofill voids at the surface of the paper but leave fibers'of the sheet'exposed between the voids after dry n tomaterials, the base to be sized is ordinarily paper as, for instance, mixed rag and wood pulp, or' sulfiteor sulfate pulp paper. 'In a modification we may use cottln, silk, rayon or other'eloth including conventional fillers' such as starchfclays, andf the like. {As the zirconium'compound, we use one that is hyi'l' ble in waterfand when suspended in finely fedfdr'm', therein, is at least somewhatgelatinous. Examples of such zirconium 'eompoundsthat rneet the requirements and give the special results described herein are' thelhydrous hydroiidejbasic' carbonate, oxide, and basic phosphate, if being understood that'the term zirconium as applied to the salts includes zircony and thatfthe ;terin' ",h ydrous as used herein means incom- 'p e ely d i the'adhesive we use a water dispersible adhesive, th ite'rm 'di sper sible including"water soluble. Examples of adhesives that illustrate the class and that we may use are glue; starch, emulsions of polyvinyl acetate, polyvinylchlo'ride and polyvinylalcohol, and magnesium aluminum silicate'known in the trade as Veeghrn;

As the photosensitive chemicalsto be usedfwe employ y of hcse hie la e u ual in maki pap s for pying engineering drawings, such as blueprint, brownprint, and positive white print papers. "Examples of such photofsensitive chemical compositions thatillustrate the kind to be used are those including the combination of ferridsalt and ferricyanide (this term includes 'feriic ferrocyanides) eombinations of ferric salts and silver salts, and 'diazo intermediates 'with' suitable coupling agents to form'azo lors o posu'reto light; 'These photosensitive mateers.

2,964,463 P ed P e 1.

or, if necessary, is to be applied in making the photosensitive a er'or applied later in a separatet featment.

Special advantages of our invention are obtained, for example, in'the making of the sorc'alled positive papers. in such papers, it-is customary for large areas of the finished copy to be white instead of blue or other back ground color expected. Our zirconium' and adhesive composition limits the penetration or the photosensitive chem ica-ls and concentrates them on the surfaceofthe paper. Asa consequence, the eitposure of the said chemicals is increased. There is decreased the proportion of unexposed chemicais which, if large, causes staining and 'discoloration of the background of the copy. The result of our process and composition is preservation in the finished py of b t n i y the e pecte v ba k nd calo As to proportions, we use sufiicient of the zirconium and adhesive compound mixture to'form a continuous film over the fibrous sheet when wet at the time of application, but'not enough to form a continuous film after the water has been evaporated therefrom; As a result we obtain a deposition of the zirconium and adhesive compound mixture in voids at the surface of the fibrous sheet without completelycovering the fibers between the voids in the dried product. As the result, the fibers in the finished product remain exposed between the voids, to receive the photosensitive orother chemical applied later.

The numerical proportions of the zirconium and adhesive mixture to be used will vary with the kind of fibrous sheet material selected as a base. Using, for instance, a paper of composition half rag fiber and half wood pulp andof thickness 0.004, We applied 1 lb. of

' zirconium paste in treating both sides of 10 lbs. of the paper. This paste contained about 15% of zirconium compound calculated as Zr0 Depending upon the paper thickness, the original size of the paper, and the absorptiveness,'we may use zirconium compound calculated'as oxide in the proportion of 0.5 part to 3 parts for parts by weight of the paper. Ordinarily we use a higher proportion, within this range,'when the paper isthin than when the paper is thick. 1

The adhesive is used in proportion to hold the zirconium compound deposited in the voids of the paper so as to prevent dustiness of the compound and also to aid in mordanting or bonding other materials applied to the paper or other fibrous "base; Suitable proportions of adhesive are about 5-20 parts for 100 parts of the zirconium paste or 30-120 parts for 100 parts of the zirconium compound calculated as oxide.

"As to conditions, we apply the zirconium compound and adhesive to the fibrous base material to be treated in any convenient manner, as by roller coating, immersion followed by squeeze rolling, or spraying on. In any case the equipment used is conventional.

' We obtain particularly desirable results, in the retention of the zirconium compound and adhesive in the surface portion of the paper and localizing of later applied photosensitive material, when the fibrous base to which the zirconium compound and adhesive are applied is in dry condition at the start of the application. Thus we may apply our zirconium compound and adhesive in aqueous suspension and'in paste form to' paper that has been passed over some at least of the drying areas of paper manufacturingequipment. In fiact, we ordinarily apply our zirconium compound and adhesive suspension either a) paper betweenthe first'and last drying sections of the paper machine or' to thefini'shed completely dried paper.

The zirconium compound and adhesive paste are applied at a pH of about 6-7.S and suitably at 6-6.5.

The invention will be further illustrated :by description inconnection with the following specific examples of the practice ofit. In these examples-and elsewhere herein proportions are expressed as parts by weight unless specifically stated to the contrary.

EXAMPLE 1 Water ml 250 Veegum (magnesium silicate), HV grade ..g 1 Carbonated hydrous zirconia ..g 25

A mixture was made of 250 ml. of water, 1 g. of Ghatti gum as adhesive, and 25 g. of carbonated hydrous zirconia of zirconium content 16% calc. as the oxide. Paper was sized in the same manner as in Example 1, dried, and sensitized with blueprint chemical. The resulting blueprint showed a deeper blue background than the paper not sized with the zirconium and adhesive composition.

EXAMPLE 3 250 ml. of water, 1 g. of Veegum I-IV adhesive, 25 g. of carbonated hydrous zirconia and 1 g. of citric acid were mixed. Blueprint paper base was sized in the usual manner, dried, the blueprint sensitizing solution was applied, the whole dried again, and blueprints made. These blueprints showed darker blue backgrounds and sharper white lines than paper not sized with our treating composition.

EXAMPLE 4 The procedure of Examples 1-3 above is followed except that the carbonated hydrous zirconia (basic carbonate) there used is replaced by other hydrous zirconium compound, particularly the hydroxide, oxide, or basic phosphate, on an equivalent weight basis calculated from the zirconia content. These zirconia compounds are used in all cases in suspension in water.

The following examples illustrate the method of preparing the hydrous zirconia compounds for use in the composition and process here described.

EXAMPLE A Preparation of carbonated hydrous zirconia gel 0.75 part of soda ash was dissolved in 152 parts of water at room temperature. A solution of zirconium oxychloride was prepared by dissolving 2.2 parts of zirconium oxychloride ZrOCl .8H- O, containing 40% by weight of Zr calculated as ZrO in 19.8 parts of water at room temperature. The resulting zirconium oxychloride solution had a density of 7.35 B.

This latter solution was added to the soda ash solution at such a rate that approximately 20 minutes were required to add the total volume. Agitation was moderate. The pH which, at the beginning was slightly higher than 10, slowly dropped to approximately 5.1 at the end of the reaction.

The precipitated slurry was allowed to age for 30 minutes and was then pumped into a plate and frame filter press at approximately 45 lbs. pressure until no further liquid flowed from the filter press. The filter cakes were then washed with water until tests with AgNO TS. indicated minimum amount of soluble chlorides. The cake was a highly gelatinous white product. It was rendered homogeneous by mixing in a pony mixer. The product gave the following analysis:

4 EXAMPLE B Hydrous zirconia gel 32.6 parts of caustic soda were dissolved in 300 parts of water. 76.3 parts of zirconium sulfate, containing 32.8% of Zr calculated as Zr0 were dissolved in 2258 parts of water in a tank provided with an efiicient type turbine agitator and equipped with radial baffles.

The sodium hydroxide solution was added to the zirconium sulfate solution at such a rate that approximately 60 minutes were required for the addition. The pH of the reaction mixture increased from a low of 1.4 at the beginning to approximately 6.1 at the end. The temperature during the reaction was maintained at 29 C.

The precipitated slurry was allowed to age for 1 hour after which it was filtered on a vacuum filter and washed free of soluble salts with water.

The resulting product was a white gelatinous material containing approximately 7.1% of Zr calculated as ZrO It will be understood that it is intended to cover all changes and modifications of the examples of the invention herein chosen for the purpose of illustration which do not constitute departures from the spirit and scope of the invention.

What is claimed is:

1. A surface-sizing composition for sizing fibrous sheet material consisting essentially of an aqueous dispersion of a water-dispersible polymeric adhesive and an incompletely dried water-insoluble hydrous zirconium compound in gelatinous condition, the adhesive and zirconium compound being in the proportion of from 30 to 120 parts adhesive to each parts of zirconium compound calculated as the oxide.

2. A surface-sizing composition in accordance with claim 1 in which the zirconium compound is hydrous zirconium oxide.

3. A surface-sizing composition in accordance with claim 1 in which the zirconium compound is hydrous zirconium carbonate.

4. A surface-sizing composition in accordance with claim 1 in which the adhesive is magnesium aluminum silicate.

5. A process of surface-sizing fibrous sheet material which comprises applying to a dry surface of the material a continuous film of the treating composition of claim 1, the film containing an amount of sizing material insutficient to form a continuous surface coating on the sheet, and then drying the film, whereby there is formed at the surface of the material a discontinuous surface size having fibers of the material exposed therebetween.

6. A process in accordance with claim 5 in which the fibrous sheet material is paper.

7. A process in accordance with claim 6 which comprises applying to the sized paper a photosensitive coating composition.

8. A surface-sized fibrous sheet material having a dis continuous surface size consisting essentially of a waterdispersible polymeric adhesive and a water-insoluble hydrous zirconium compound in the proportion of from 30 to parts of adhesive to each 100 parts of the zirconium compound calculated as the oxide.

9. A photosensitive sheet comprising a surface-sized fibrous base in accordance with claim 8 and a photosensitive coating thereover.

References Cited in the file of this patent UNITED STATES PATENTS 1,530,139 Ryan Mar. 17, 1925 1,896,040 Ruben Jan. 31, 1933 2,237,374 Smith Apr. 8, 1941 2,517,111 Jahoda Aug. 1, 1950 2,647,835 Weaver Aug. 4, 1953 2,721,801 Clark et a1. Oct. 25, 1955 2,751,309 Baxter June 19, 1956 2,754,280 Brown et a1. July 10, 1956 2,759,847 Frost et al Aug. 21, 1956 

1. A SURFACE-SIZING COMPOSITION FOR SIZING FIBROUS SHEET MATERIAL CONSISTING ESSENTIALLY OF AN AQUEOUS DISPERSION OF A WATER-DISPERSIBLE POLYMERIC ADHESIVE AND AN INCOMPLETELY DRIED WATER-INSOLUBLE HYDROUS ZIRCONIUM COMPOUND IN GELATINOUS CONDITION, THE ADHESIVE AND ZIRCONIUM COMPOUND BEING IN THE PROPORTION OF FROM 30 TO 120 PARTS ADHESIVE TO EACH 100 PARTS OF ZIRCONIUM COMPOUND CALCULATED AS THE OXIDE. 